This application is based on application No. 11-106771 filed in Japan, the content of which is hereby incorporated by reference.
(1) Field of the Invention
The present invention relates to a technique to protect a copyright on a digital production and more specifically to a technique to restrict use of digital data, such as music, stored on a recording medium such as a compact disc (CD), based on the number of times the digital data has been used. Here, to xe2x80x9cusexe2x80x9d digital data on a CD means to read the data from the CD, reproduce the data, or record the data onto another recording medium.
(2) Description of the Prior Art
The widespread use of personal computers (PCs) and developments in Internet technology have enabled digital data, such as music and computer programs, to be widely distributed and used.
For instance, the MP3 JUKEBOX application program developed by SUMITOMO METAL Systems Development Co., Ltd. allows the user to freely create a copy of music digital data written on a CD, using a PC. According to this application program, music digital data written on a CD is read and compressed into a small-sized MP3 (MPEG1 Audio Layer-3) format, which is one of compression formats standardized by MPEG (Moving Picture Experts Group) for audio data. By compressing a large amount of data, such as music, into a small amount of data according to MP3, which performs irreversible compression at a high compression rate, the data can be quickly distributed via a communication line whose band width is small, or written onto a small-capacity recording medium.
As another example of technology contributing to widespread use of digital data, portable music playback devices, such as RIO developed by Diamond Multimedia Systems, Inc., which play music data in an MP3 format present on flash memory, have appeared on the market.
The following briefly describes a digital data recording system that uses the MP3 JUKEBOX application program.
FIG. 1 is a block diagram showing functional components of the conventional digital data recording system.
This digital data recording system can be achieved by a PC that comprises a CPU, memory, a reader that reads a digital signal from a CD, and storage such as a hard disk unit. In terms of functions, this system comprises a data read unit 91, a recording unit 92, and a data storage unit 94.
The data read unit 91 reads music digital data stored on a CD 93, and the recording unit 92 converts the read data into an MP3 format and places it into the data storage unit 94, which is a recording medium such as a hard disk. Functions of the data read unit 91 and the recording unit 92 can be realized by the CPU executing the application program stored in the memory.
The user can use the digital data, which has been stored in the data storage unit 94, for instance, by having an application program that controls music reproduction process the digital data, or recording it into flash memory in the aforementioned portable music record/playback device after connecting this record/playback device to the PC.
However, the above digital data recording system, which does not have the provision for restricting creation of a copy of digital data, has a drawback in that copyrights of digital productions cannot be protected.
Serial Copy Management System (SCMS) is a scheme to protect copyrights of digital productions by preventing digital data from being repeatedly copied. SCMS is built into an audio appliance which has a function to create a copy of digital data, including music, which is written on a recording medium such as a CD, and to transfer the copy onto another writable recording medium such as a Mini Disc (MD). Such an audio appliance with the SCMS built in can prevent a first-generation copy recorded by the user on an MD or the like from being copied again, that is, prevent a second- or higher-generation copy from being created.
However, SCMS does not prevent users from making numerous first-generation copies. This means that implementing SCMS in devices that can copy digital data from one medium such as a CD onto another does not stop users of such devices from making any number of first-generation copies that may end up being distributed illegally.
In view of the above problems, the present invention aims to provide a digital data processing device that restricts creation of a first-generation copy of digital data, such as music, present on a recording medium such as a CD, based on the number of times the digital data has been copied.
Since digital data is used in a variety of ways, the present invention also aims to provide a digital data processing device which restricts usage, other than just copying, of digital data present on a recording medium, based on a number of times the digital data has been used.
In order to achieve the above objects, the digital data processing device of the present invention (1) reads content data from a first recording medium which also stores ID (identification) information, and (2) uses the read content data, the digital data processing device including: a limit information storage unit for storing limit information showing a limit on a number of times the content data is permitted to be used: a use information storage unit that has a storage region capable of storing a combination of: (1) the ID information present on the first recording medium; and (2) use information showing a number of times the content data has been used; an ID information reading unit for reading the ID information from the first recording medium; a use judging unit for: (1) referring to the use information storage unit to obtain the use information that is in the same combination as the read ID information; (2) comparing the number of times in the obtained use information with the limit in the limit information; and (3) judging whether usage of the content data is permitted based on a comparison result; and a content data using unit for using the content data if the use judging unit has judged that the usage of the content data is permitted, and updating the use information each time the content data is used.
With the above construction, the digital data processing device associates a number of times content data present on a recording medium has been used with ID information, which is also present on the recording medium, as one combination. The digital data processing device then judges whether to permit usage of the content data based on this number of times to restrict usage of the content data. Accordingly, the present invention can be used to protect benefits of copyright holders of productions.
Since the above combination, based on which the above judgement is made, is stored in a storage region, not on the first recording medium, the first recording medium does not need to have a space for storing information such as for the combination. This also enables the present digital data processing device to restrict usage of content data present on a read-only medium.
Here, the content data using unit may contain a recording unit that accesses a second recording medium to write data, and uses the content data by having the recording unit write the content data onto the second recording medium.
The above digital data processing device can restrict recording, that is, copying of content data present on one recording medium onto another, based on a number of times the content data has been copied. This can prevent users from making numerous first-generation copies of music, for instance, stored on a recording medium such as a CD.
Here, the ID information stored on the first recording medium may specify the content data present on the first recording medium.
The above digital data processing device can restrict creation of certain content data based on a number of times the content data has been used regardless of a recording medium on which the content data is present. This allows, for instance, a copyright holder to control a permitted number of copies of content data.
Here, when the read ID information does not exist in the use information storage unit, the use judging unit may (1) assume that use information, which would be in a same combination as the read ID information, shows a number of times0, and (2) obtain the use information showing the number of times0, and the content data using unit may place, instead of performing an update, a combination of: (1) the read ID information; and (2) use information, which shows 1 as a number of times the content data has been used, into the use information storage unit.
With the above construction, the digital data processing device can restrict usage of content data, based on a number of times the content data has been used after recording the content data for the first time. Accordingly, when the limit xe2x80x9c0xe2x80x9d, for instance, is set, it is possible to completely prohibit usage of content data.
Here, the limit in the limit information may correspond to the ID information and show the limit on the number of times the content data, which is present on the first recording medium together with the ID information, is permitted to be used, and the use judging unit may compare the number of times in the use information with the limit corresponding to the read ID information, and judge that usage of the content data is permitted when the compared number is smaller than the limit.
With this construction, usage of content data can be restricted according to ID information corresponding to the content data. This is to say, usage of content data can be restricted according to the content of the content data, regardless of a recording medium on which the content data is present.
Here, the use information may be expressed as a number, and the content data using unit may update the use information by incrementing the number by one, and when the incremented number of times has become equal to the limit in the limit information, the content data using unit may delete a combination containing the updated use information from the use information storage unit, and update the limit to0.
This construction prevents sizes of storage regions, which are present in the digital data processing device and are used to store use information, from continuing to increase each time content data on a different recording medium is used.
Here, the first recording medium may be read-only.
For this construction, the digital data processing device can restrict copying of content data, which is present on a read-only medium such as a CD, based on a number of times the content data has been copied.
Here, the content data may be audio data and/or image data.
For this construction, the digital data processing device is capable of preventing users from unrestrictedly making copies of audio data and/or image data present on a recording medium.
Here, the content data may be audio data, and the first recording medium may be a compact disc. The ID information may be an ISRC (International Standard Recording Code).
For this construction, the digital data processing device is capable of restricting recording of certain music specified by an ISRC onto a recording medium, based on a number of times the content data has been recorded.
Here, the ID information present on the first recording medium may distinguish the first recording medium from other recording media.
With this construction, the digital data processing device is capable of restricting, for each recording medium, a number of times content of the recording medium can be recorded onto another medium.
Here, the content data may be divided into a plurality of sets of partial content data, and the ID information may contain a plurality of sets of part-ID information, each set of part-ID information specifying a different set of partial content data. The ID information reading unit may read a set of part-ID information specifying a set of partial content data, and the use judging unit may judge whether usage of the set of partial content data specified by the read part-ID information is permitted.
With this construction, the digital data processing device is capable of restricting copying of each song, for instance, present on one recording medium based on a number of times the song has been copied.
Here, the content data may be audio data and/or image data, and the content data using unit may include a reproducing unit that reproduces sounds and/or images from the audio data and/or the image data, and use the content data by having the reproducing unit reproduce sounds and/or images from the content data.
With this construction, the digital data processing device is capable of restricting reproduction of data such as music data present on a recording medium such as a CD by setting a limit on a number of times the music data can be reproduced. This is useful, for instance, for restricting a number of times users can play a sample music CD at no charge.